
var xmlHttpRequest = null;

function createXHR() {
    try{
        xmlHttpRequest = new XMLHttpRequest();
    }catch (e1) {
        var _msxmlhttp = new Array("Msxml2.XMLHTTP.6.0",
            "Msxml2.XMLHTTP.5.0","Msxml2.XMLHTTP.4.0","Msxml2.XMLHTTP.3.0",
            "Msxml2.XMLHTTP","Microsoft.XMLHTTP");

        for (var i=0;i<_msxmlhttp.length;i++){
            try{
                xmlHttpRequest = new ActiveXObject(_msxmlhttp[i]);
                if(xmlHttpRequest!=null){
                    break;
                }
            }catch (e2) {

            }
        }
    }

    if(xmlHttpRequest == null){
        alert("不能创建Ajax对象！")
    }
}

function sendRequest(url,params,method,handler) {
    createXHR();
    if(!xmlHttpRequest) return false;
    xmlHttpRequest.onreadystatechange = handler;
    if(method == "GET"){
        xmlHttpRequest.open(method,url+'?'+params,true);
        xmlHttpRequest.send(null);
    }
    if(method == "POST"){
        xmlHttpRequest.open(method,url,true);
        xmlHttpRequest.setRequestHeader("Content-type","application/x-www-form-urlencoded");
        xmlHttpRequest.send(params);
    }
}